Japanese Laid-Open Patent Publication No. 2009-12153 describes an example of an electric power tool provided with a drilling function such as a drill driver. Such an electric power tool is used with a bit, such as a drill or a hole saw, to bore a hole in a plate of wood, steel, or the like.
A user manipulates a trigger of an electric power tool provided with a drilling function so that the rotation speed of a motor changes in correspondence with the pulled amount (manipulation amount) of the trigger. As the pulled amount of the trigger increases, the rotation speed of the motor, or the bit, increases.